Need to configure the SMTP banner on a SonicWALL TZ series router, like a TZ 400 for example? The thing about configuring the SMTP banner on a SonicWALL TZ series router, is that you can’t!

SonicWALL suggest that since you can’t set up the SMTP banner on the TZ series router, you should consider setting your reverse DNS record to point to the SMTP banner SonicWALL uses. If you want to go down this line, you can find the SMTP banner your SonicWALL is currently using through MXToolbox’s Test Email Server check. Personally, my recommendation is just to leave the SMTP banner as incorrect, otherwise you’ll get another issue that your reverse DNS does not point to a valid hostname.